Air-delivered anti-personnel mine



March 30, 1965 E. G. REED, JR

AIR-DELIVERED ANTI-PERSONNEL MINE Filed Nov.. 27, 1962 4 Sheets-Sheet lff fl Il V 7 los 122 BO t [4a INVENTOR .Zeed/.Ji'

Edwin By Z;

ATTORNEY March 30; 1965 E. G. REED, JR 3,175,489

AIR-DELIVERED ANTI-PERSONNEL MINE l Filed Nov. 27, 1962 4 Sheets-Sheet 2INVENTOR 84 Edwin Qfeed, fr?

ATTORNEY Filed Nov. 27, 1962 March 30, 1965 E. .1.Rr-:ED,'JRl

4 AIR-DELIVERD ANTI-PERSONNEL MINE 4 Sheets-Sheet 3 sa n2 |02 looINVENTOR Edwin ATTORNEY March 30, 1965 E. G. REED, .JR 3,175,489

' AIR-DELIVERED ANTI-PERSONNEL MINE Filed Nov. 27, 1962 4 Sheets-Sheet 4INVENT OR .62 Edwin leage BYM;

ATTORNEY United States Patent tiice 3,175,480 Patented Mar. 30, 19653,175,489 AIR-DELIVERED ANTI-PERSONNEL MINE Edwin G. Reed, Jr., 18937Nordhei St., Northridge, Calif. Filed Nov. 27, 1962, Ser. No. 240,465 4Claims. (Cl. 102-8) (Granted under Title 35, U.S. Code (1952), sec. 266)The invention described herein may be manufactured and used by and forthe Government of the United States of America for governmental purposeswithout the payment of any royalty thereon or therefor.

This invention relates to anti-personnel mines and is concerned moreparticularly with an air-delivered antipersonnel land mine.

It is an object of the invention to provide an antipersonnel mine thatcan be delivered in large numbers by service aircraft without aircraftmodification.

A further object is to provide an anti-personnel mine that can be madecheaply, in large numbers, without using scarce materials or requiringnew production facilities.

Additional objects are to provide an anti-personnel mine that: can bedelivered from any altitude; can be used in any terrain, includingjungle areas; will not be activated until after impact with the ground;will have a lethal radius of at least about ten feet against unarmored.armed personnel; will rise about ten feet from impact before exploding,thereby substantially maximizing its lethal radius; will remain armed inplace for at least three months; can be stored indeiinitely withoutdeterioration.

Further objects and advantages of the invention will appear as thedescription proceeds.

The invention will be better understood on reference to the followingdescription and the accompanying drawing, wherein:

FIG. l is a longitudinal cross-sectional view of an antipersonnel landmine embodying features of the invention, at linception of free fall.

FIG. 2 is an elevational view of the same.

FIG. 3 is an elevational View showing how several of the mines aremaintained in a string in an aircraft.

FIG. 4 is an elevational schematic View showing a parachute-supportedstring of mines.

FIG. 5 is an enlarged View, partly in section and partly in elevation,of the magnetic switch-and-float assembly appearing in the upper part ofFIG. 1, the switch being unable to close.

FIG. 6 is a plan sectional View taken as indicated at 6-6 in FIG. 5.

FIG. 7 is a sectional View of a detail of the switch-and oat assembly.

FIG. 8 is an elevational view taken as indicated at 8-8 in FIG. 7.

FIG. 9 is a diagram of the incomplete circuitry enibodied in the minebefore impact with the ground.

FIG. l0 is an elevational view of the mine in free fall.

FIG. 11 is similar to FIGS. 1 and 8 but shows the changed relation ofparts resulting from impact of the mine with the ground.

FIG. 12 shows the circuitry completed pursuant to impact, but with theswitch still unable to close.

FIG. 13 is similar to the upper part of FIG. 9 but shows the magneticswitch-and-float assembly aiioat, with the switch still unable to close.

FIG. 14 shows the circuitry corresponding to FIG. 13.

FIG. 15 is similar to FIG. 13 but with the magnetic switch able toclose.

FIG. 16 is a sectional View taken at 16-16 in FIG. 15, showing only themagnetic switch.

FIG. 17 shows the circuitry with the magnetic switch able to close.

Referring now to the drawing, depicting an illustrative embodiment ofthe invention, there is shown at 10 (FIGS. 1 and 2) a mine as the partsthereof are arranged when the mine begins its free fall. The mine 10includes a melamine formaldehyde resin or other suitable barrel orhousing 12 comprising a cup-like tube 14 closed at the top by a cap 16threaded at 18 thereto. The lower part 20 of the tube 14 is thickenedinward and encases a cup-like liner 22 which is to function as anelectrode of an electric cell, as will appear, and may be formed ofcarbon and manganese dioxide or other suitable electrode material. Thetop 24 of the thickened portion 20 provides a seat for the outwardlyprojecting rim 26 of the liner 22, and may be chamfered for thatpurpose. The liner 22 in turn has a protective cup-like liner 28 ofblotting paper or other suitable porous material.

Seated on the bottom 32 of the protective liner 28 is a capsule 34comprising a hollow frangible sphere 36 of glass or other suitablematerial containing an electrolyte 38, such as a solution of ammoniumchloride and zinc chloride. A protective blotting paper or othersuitable porous disc pad 40 overlies the sphere 36.

The mine 10 also includes a missile in the form of a plunger 44 havingat its bottom a grenade 46 of reduced diameter. The grenade 46 comprisesa Zinc or other suitable shell 48 which is to function as the otherelectrode of the electric cell. rThe shell 4S comprises an externallyserrated cup 50 and a cap 52 threaded at 54 into and seated on the rim56 of the cup. The cup 50 projects down into the space 58 defined by theblotting paper 28 and 40, and contains a bursting charge 60 and abooster charge 62. The cap 52 has an axial bore 64 therethrough, filledbelow the top with a slow-burning type of solid rocket propellant 66.

The plunger 44 also includes a molded plastic block 70 of melamineformaldehyde resin or other suitable material externally threaded at 72to the grenade cap 52 and having a bottom central recess 74 forming withthe upper end of the caps bore 64 a pocket in which an electricaligniter 76 is disposed in spaced relation, as indicated at 78, to thetop of the propellant 66. A brass or other suitable metal ring 80 iscast in the part of the block 70 directly over the cap 52 and projectsdownward out of the block and is firmly seated in an annular groove 82in the top of the cap. A wire 84 cast in the block 70 is connected tothe ring 80. The wire 84 and a tine copper wire 86, insulated withmelamine lacquer or other suitable material and also cast in the block70, project into the recess 74 and are connected to and support theigniter 76. Vents SS bored in the cap 52 establish communication betweenthe space 73 and the annular space exterior to the cap. A second brassor other suitable metal ring 92, cast in the lower outer peripheralportion of the block 70, projects downward therefrom and about andspaced from the grenade 46 and directly over the rim 26 of the liner 22.An insulated wire 94, like the wire d6, is cast in the block 70 andconnected to the ring 92.

The block 70 is formed in its upper side with a hemispherical cavity 96containing an inverted cup-like wood or other suitable float 98 in whichis riveted at 100 the hub 102 of a brass or other suitable metalcruciform spider 104 (FIGS. 5, 7 and 8) whose legs 106 project downwardbeyond the rim 108 of the float. A smaller inverted cup-like wood orother suitable float 110 below and spaced from the base 112 of the float98 is located within the contines of and spaced from the spider 104.Electrically connected crossed magnetic needles 114 l(see also FIGS. 5and 6) pass through and are securely held by the float 110. The needles114 are spaced below the base 116 of the iioat 110, and the needle poles118 and 120 sure/reo project into circumferentially spaced andalternating relation to the spider legs 106 and form therewith an openmagnetic switch 122 (FIG. 9) which, as will appear, cannot close untilafter an interval of time following impact of the mine with the ground.The wire 86 projects into the cavity 96, passes upward in coiled form,as at 124 (FIGS. 5 and 6), into the interior 126 of the iioat 110, andis electrically connected to the needle juncture 128. The wire 94projects into the cavity 96, passes upward in coiled form, as at 130,into the interior 126 of the float and about the coil 124, is securedaxially in the base 116 of said float, and has an upper end portion 132electrically connected to the spider hub 102. The spider legs 106 andneedle poles 118 and 120 are cast in an acetone-soluble sleeve 124(shown also schematically in FIG. 9) extending upward to the rim 108 ofthe ioat 9S, the bottom of the sleeve being secured by an acetonesolubleadhesive 136 to the bottom of the cavity 96. It is manifest that thesleeve 134 prevents closing of the switch 122.

A complemental molded plastic block 138 of melamine formaldehyde resinor other suitable material is threaded at 140 to the upper rim of theblock 70 and forms therewith a piston 142 having a sliding fit in theunthickened portion 144 of the tube 14. The block 138 has ahernispherical cavity 146 complemental to the cavity 96 and containing asolution of acetone 148 and partitioned from the cavity 96 by a serratedglass or other suitable fran gible disc 150 held in place by the blocks78 and 138. The block 138 has an upper end portion 152 of reduceddiameter to accommodate thereabout a coil spring 154 and provide anannular edge 156 between which and the top of the housing cap 16 thespring is compressed.

The bottom of the housing 12 is closed and converges downward, and isencased in a brass or other suitable rugged cup 160 threaded at 161 tothe housing and having a spike-like bottom 162.

A plastic or other suitable sleeve 164 about the housing 12 has at itsbottom a collar 166 secured as by plastic or other suitable adhesive tothe housing above the rim of the cup 160 and is cut above the collar toprovide upwardly extending longitudinal fingers or ribbons 168.

The housing 12 and block 70 are respectively formed with diametral holesand 172 for accommodating a removable safety locking pin 174 to preventdrop of the plunger 44 in the housing 12 prior to free fall of the mine10, as will appear. The fingers 168 lianking the ends of the pin 174 arenotched (not shown) to clear the ends of the pin.

Prior to free fall of the mine 10, the fingers 168 are held against thehousing 12 by a removable fabric belt 176 about the upper end of thehousing. A steel Cotter 178 is connected as by a ring 180 (FIG. 2) to anextension 182 of the belt 176 and snugly passes through a hole 184 inthe tip 186 of the safety pin 174 of the next one of a series of mines18. The mines 10 are maintained in a string 188 by means of a strandedsteel cable 190 (FIGS. 3 and 4) passing through the eyes 192 of the pins174 of the several mines, the cable having a pair of steel stops 194straddling each eye. The string of mines is loaded into a steel box 196designed for the dispensing of the mines from an aircraft (not shown) bymeans of a parachute 198 connected to the end 200 of the cable 190, thebox being placed at a hatch of the aircraft.

Inasmuch as there will be no mine-carried cotter 178 for the pin 174 inthe last mine, indicated at 202 (FIGS. 3 and 4) of the string 188, thereis anchored to the box 196 a cord or ribbon 204 having at its free end acotter 206 received in the hole 184 in the pin tip 186 of said lastmine.

When the parachute 198 is released from the aircraft and enters theslipstream, the parachute pulls the cable 190 and thus the string 188 ofmines 10 out of the box 196 and into theslipstream. The last mine 202 inits descent tenses the ribbon 204, and the safety pin end 186 of thelast mine is then pulled free of the cotter 206, whereupon said mine,with its belt 176, slips from its safety pin 174, and falls. As the mine202 falls, it pulls its Cotter 178 out of the safety pin end 186 of thenext mine 10 in the string 188, and thereupon said next mine slips freeof its safety pin 174 and falls with its belt 176. Thus, in a chainreaction all of the mines are successively released for fall.

Each belt 176 loosely girds the respective mine, so that, as each mineis thus released and starts its fall, its belt is blown olf by the rushof air, whereupon the fingers 168 spring out and collectively assume theared formation shown in FIG. 10 and thus operate to stabilize theattitude of the free-falling mine with its spike 162 lowermost.

With removal of the safety pin 174, the spring 154 is released to theextent of depressing the plunger 44 slightly so that the plunger issupported by the capsule 34, as is apparent from FIG. 1.

Prior to impact of the mine 10 with the ground, the electric circuit ofthe mine is incomplete, as indicated at 208 (FIG. 7), lacking as it doesa source of electric energy.

The force of the impact of the mine with the ground causes the mine tobecome imbedded in the ground and causes the plunger 44 to plunge in thehousing 12 and hence the grenade 46 to shatter the frangible container36 (FIG. 11), freeing the electrolyte 38, which readily seeps throughthe blotting paper 28 into contact with the electrode 22 and through theblotting paper 40 into contact with the electrode 50, thereby creating abattery cell 210 (FIG. l2). The plunge of the plunger 44 is stopped byengagement of the brass ring 92 with the rim 26 of the electrode 22(FIGS. 11 and 12), and the plunger is held in this position by thespring 154.

Also at the impact, the partition 158 shatters, allowing the acetonesolution 148 to descend into the cavity 96. The acetone solution 148then dissolves the adhesive 136 and thus frees the sleeve 134 from thebottom of the cavity 96. Thereupon the slack in the wires 86 and 94,afforded by their respective coils 124 and 130, permits the rigidswitch-and-float assembly to ascend in the acetone 148 to a level (FIG.13) at which the assembly is moored by the now unslacked wire 94, withthe sleeve 134 immersed in the acetone, and the needles 114 horizontal.FIG. 14 is like FIG. 12 except for the absence of the coils 124 and 130,as the coils are unslacked at this stage. On dissolution of the adhesive136, the assembly, if not then magnetically azimuthally oriented by themagnetic eld local to the mine, will so orient itself. During and afterthe orientation, the acetone 148 continues to dissolve the sleeve 134.When the sleeve 134 is dissolved, the iioat 98 is moored to the oat 110by the wire portion 132 (FIG. 15), with the needle poles 118 and 120still in their original spaced relation to the respective spider legs106 so long as the magnetic field local to the mine is undisturbed, theswitch now being able to close (FIGS. 16 and 17).

With the mine 10 in the condition just described, then, when themagnetic field local to the mine is disturbed, as by a rifle or othersteel object which may be borne by a soldier, the magnetic needles 114rotate and of course cause the small iioat 110 also to rotate. Due tothe inertia of the large float 98 and attached spider 104 and thereadiness with which the fine wire portion 132 twists, the large floatand spider remain substantially stationary, with the result that theneedle poles 118 and 120 are arrested by the spider legs 106 and therebyclose the switch 122 (FIG. 17), completing a circuit to the igniter 76.The burning igniter 76 ignites the slow burning rocket propellant powder66, the gases of combustion escaping through the vents 8,8 to theannular space 90 (FIG. 1l). The buildup in gas pressure in the space 90acts on the piston 142 to propel the plunger 44 upward, the plungershattering the plastic housing cap 16 and' liftingV the plunger to aheight of about ten feet. Substantially at the zenith of the flight ofthe plunger 44, the burning powder 66 -ignites the booster charge 62which in turn ignites the bursting charge 60, exploding the grenade 46,which thus can have an injurious or lethal effect on personnel in alarge region.

The solvent 148 and the substances 134 and 136 soluble therein may be ofany suitable character. If the solvent 148 is a ketone, of which acetoneis an example, the substances 134 and 136 may be an acrylic resin, suchas a methyl methacrylate polymer, of which Lucite is an example. Thesolvent 148 is provided in suicient quantity to assure promptdissolution of the substances 134 and 136.

It is apparent that the invention may be practiced with the use ofnon-scare materials, and will accomplish the objects specifically setforth in and implicit from the foregoing.

Obviously many modifications and variations of the invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

I claim:

1. In an air-delivered anti-personnel land mine,

(a) a barrel having means for maintaining the barrel in a substantiallyupright attitude in free fall;

(b) the barrel having a spike-like bottom to plant the barrelsubstantially upright in the earth;

(c) an unarmed grenade in the barrel; and

(d) means responsive to planting of the barrel in the earth for armingthe grenade;

(e) said means including magnetically controlled means operative inresponse to a disturbance of the local magnetic lield for iiring thegrenade upward out of the planted barrel and into the air and explodingthe grenade while the grenade is in the air.

2. In an anti-personnel land mine,

(a) a barrel to be dispensed from the air;

(b) means for maintaining the barrel substantially upright during freefall;

(c) the barrel having a sharply-pointed bottom to enable the barrel tobe embedded substantially upright in the earth;

(d) an unarmed grenade in the barrel;

(e) a liquid electrolyte capsule in the barrel below the grenade;

(f) the capsule being breakable by the grenade on impact of the barrelwith the earth to free the electrolyte;

(g) a member adjacent the capsule and spaced from the grenade;

(h) the member and the grenade casing being respectively formed ofmaterials which, in contact with the electrolyte, will serve aselectrodes of an electric cell including the electrolyte;

(i) the grenade casing and the member being simultaneously contactibleby the freed electrolyte; and

(i) means including the cell for arming the grenade.

3. The structure of claim 2,

(k) the barrel being frangible and closed,

(l) said means including a magnetic switch responsive to disturbance ofthe local magnetic eld for firing the armed grenade upward through thebarrel and into the air and exploding the grenade while the grenade isin the air.

4. The structure of claim 2,

(k) a iirst contact carried by and insulated from the grenade anddisposed over and spaced from said member while the capsule is intact;

(l) means operative on the breaking of the capsule for holding thecontact in engagement with said member;

(m) an electrical insulator body connected to the grenade and having rstand second compartments;

(n) a frangible partition hermetically separating the compartments andbeing breakable on impact of the barrel with the earth;

(o) a non-electrolytic solution in only the lirst compartment andcapable of gravitating into the second compartment on the breaking ofthe partition;

(p) a lower float in the second compartment;

(q) a magnetic needle secured to the lower float;

(r) an upper iloat in the second compartment;

(s) a second contact secured to the upper iloat and spaced from theneedle poles and forming with the needle a switch;

(t) the body, partition and floats being insoluble in the solution;

(u) a rst wire anchored in the body and electrically connecting theneedle to the rst contact and having a slack portion in the secondcompartment;

(v) an electrically activated igniter electrically connected to thegrenade casing;

(w) a second wire anchored to the body and electrically connected to theigniter and having a slack portion in the second compartment;

(x) an electrical insulator soluble in the solution;

(y) the second contact, needle, and slack portions being cast in theinsulator;

(z) a third wire secured to and extending between the floats andelectrically connected to the second contact and to the slack portion ofthe second wire; and

(aa) an adhesive soluble in the solution and adhesively securing theinsulator to the second compartment;

(bb) the floats, second contact, needle, insulator, slack portions andthird wire being floatable as a unit in the solution when the partitionis broken;

(cc) the wires being substantially non-resistant to torsion when twistedless than whereby, on breaking of the partition and dissolution of theadhesive, the unit will float in the solution and assume a position inwhich the needle is oriented north and south, and, on dissolution of theinsulator, the irst wire will moor the lower oat, the third Wire willmoor the upper oat to the lower oat, the needle poles will remain inspaced relation to the second contact until the magnetic iield local tothe mine is disturbed, and engagement of one of the poles with thecontact will close an electric circuit which will activate the igniter.

References Cited by the Examiner UNITED STATES PATENTS 1,239,134 9/17Steel 102-7.2 X 1,300,333 4/19 Berry 102--5 1,318,926 10/19 Settle 102-42,044,819 6/36 Taylor 102-4 2,062,674 12/ 36 Pirwitz 20G-84 2,245,1256/41 Chambers 200-84 2,374,179 4/45 Delalande 102-8 2,376,227 5/45 Brownl02-7.2 X 2,397,137 3/46 Glennon et al 102-18 X 2,399,242 4/46 Metcalfe102-64 X 2,412,742 12/46 Muiy 102-18 X 2,440,702 5/48 Short 102-82,453,715 11/48 Liljigren 102-8 2,682,567 6/54 Porter 102-702 2,690,1229/ 54 Darnall et al. 102-72 2,826,990 3/59 Gross 102-8 2,931,848 4/60Burrell LOZ-70.2 X 2,972,946 2/61 Poulter lO2-7.2

BENJAMIN A. BORCHELT, Prmay Examiner.

SAMUEL W. ENGLE, Examiner.

1. IN AN AIR-DELIVERED ANTI-PERSONNEL LAND MINE, (A) A BARREL HAVING MEANS FOR MAINTAINING THE BARREL IN A SUBSTANTIALLY UPRIGHT ATTITUDE IN FREE FALL; (B) THE BARREL HAVING A SPIKE-LIKE BOTTOM TO PLANT THE BARREL SUBSTANTIALLY UPRIGHT IN THE EARTH; (C) AN UNARMED GRENADE IN THE BARREL; AND (D) MEANS RESPONSIVE TO PLANTING OF THE BARREL IN THE EARTH FOR ARMING THE GRENADE; (E) SAID MEANS INCLUDING MAGNETICALLY CONTROLLED MEANS OPERATIVE IN RESPONSE TO A DISTURBANCE OF THE LOCAL MAGNETIC FIELD FOR FIRING THE GRENADE UPWARD OUT OF THE PLANTED BARREL AND INTO THE AIR AND EXPLODING THE GRENADE WHILE THE GRENADE IS IN THE AIR. 